Enter the world of Azeroth and battle against the Alliance of humans, dwarves and night elves or the brutish orcs, trolls and undead of the Horde. World of Warcraft has a very large community of players with hundreds of servers and a myriad of endgame pursuits from raiding dungeons, questing, achievement hunting, PVP arenas, and now pet battles.

World of Warcraft is the game that launched a thousand MMOs. Soon after Blizzard released it in 2004, World of Warcraft surpassed EverQuest as the MMO with the highest population and over the next few years grew to 12 million subscribers. Even after successful expansions like the latest Mists of Pandaria, the population has dipped to below 10 million, but WoW continues to entertain a large portion of the MMO audience.

Part of what made WoW successful is that it's easy to learn but hard to master. The starting areas for new characters make it extremely easy to begin your career with strong story element and helpful tooltips. At the level cap, now at level 90 in Mists of Pandaria, the raid encounters are extremely challenging and the PVP in instanced battlegrounds and arenas are hotly contested.

The classes have evolved over time, but the holy trinity of MMOs are well-represented with flavorful classes like shaman and paladins (now open to both factions), demon-controlling warlocks, nature-loving druids and ranged attacking hunters, as well as staples like warrior, mage, and priests. A huge overhaul to the talent system for MoP allows the player to concentrate in areas without it being necessary to have one build or another to be successful.

While grouping and guilds is a large focus in the game, WoW offers a lot of content for the solo player including questing in four expansions worth of zones and a robust achievement system that rewards players for crafting and collecting of items like cosmetic minipets. With MoP, Blizzard introduced a Pokemon-like pet battle system that pits the mini-pets against one another. It's quite fun and Blizzard states there's a huge crossover between the hardcore PVP players and pet-battle enthusiasts.